Engine oil pump provided automatic adjustment of oil supply amount

ABSTRACT

An engine oil pump includes an oil supply mechanism and an adjustment mechanism. The oil supply mechanism includes an oil inlet, an oil outlet, an oil passage with two ends communicating with the oil inlet and oil outlet, and a driving gear and a driven gear located in the oil passage. The driving gear and driven gear are engaged at a selected depth to determine oil supply amount passing through the oil passage. The adjustment mechanism includes a housing and an actuation piston fastened to the driven gear. The housing has an engine oil duct on the periphery including one end communicating with the oil outlet and introducing engine oil from the oil outlet to one side of the actuation piston for storing. The actuation piston is pushed by pressure of the engine oil to drive the driven gear to move, and the oil supply amount is also changed.

FIELD OF THE INVENTION

The present invention relates to an engine oil pump that provides automatic adjustment of oil supply amount and particularly to an engine oil pump to supply engine oil to an internal combustion engine.

BACKGROUND OF THE INVENTION

When an internal combustion engine is in operation to generate driving power, the piston is moved constantly and reciprocally in a cylinder at high speed to compress fuel and air mixture and ignite for combustion. If there is lack of lubricant to provide lubrication, cleaning and cooling, the cylinder is rapidly damaged by the piston and results in incapable of operation of the engine. Hence supplying the lubricant to the cylinder is a necessary function of the internal combustion engine. Although the lubricant can provide smooth movement of the piston, its viscosity and supply amount also affect performance of piston operation. For instance, if supply amount of the lubricant is insufficient, protection effect suffers. On the other hand, if supply amount of the lubricant is too much, more engine output power is consumed and driving power output drops. Moreover, required amount of the lubricant on various engine elements and engine rotational speed are not in a linear relationship. When the engine rotational speed increases, the lubricant needed for the engine elements reduces. Hence when the engine is operated at high speed, lubricant pump tends to bring too much lubricant into the engine elements and result in unnecessary oil supply and engine power consumption. The conventional lubricant pump supplies a fixed amount of lubricant. For instance, R.O.C. patent No. 570096 entitled “Engine and engine oil pump positioning apparatus” with its abstract discloses: “An engine and engine oil pump positioning apparatus mainly provides a centric positioning mechanism interposed between the engine body and engine oil pump. The centric positioning mechanism includes a jutting ring located at one side of the engine body centric with the crankshaft, and a coupling ring located at a corresponding side of the engine oil pump centric with an axle hole of an inner rotor. The coupling ring has an outer diameter the same as an inner diameter of the jutting ring of the engine body. The crankshaft is coupled in the axle hole of the inner rotor of the engine oil pump with the coupling ring is centrically coupled on the jutting ring to position the engine oil pump on the engine body. By means of the centric positioning approach, the axle hole of the inner rotor of the engine oil pump can be coupled accurately on the crankshaft to improve precision and facilitate assembly and installation”. While the aforesaid technique discloses the centric positioning mechanism interposed between the engine oil pump and engine body and centric with the crankshaft and axle hole of the inner rotor to enhance positioning precision and facilitate assembly of the engine oil pump and engine body. The crankshaft is rotated to drive the engine oil pump and merely directs engine oil from an oil inlet to an oil outlet and then introduces into the engine body.

R.O.C. patent No. 1284177 entitled “Motorcycle engine oil pump” with its abstract discloses the motorcycle engine oil pump at least including an engine oil pump, a water pump, a driving shaft, a bracing rack, a driving gear and an oil collection cap. The engine oil pump has one end supported by a crankshaft box and another end coupled with the driving shaft. The driving shaft is coupled with the driving gear close to a distal end thereof. The driving gear is coupled with a crankshaft through a driving chain. The oil collection cap is located at an outer side of the driving gear. The distal end of the driving shaft is coupled with a driven shaft of the water pump. The crankshaft drives the driving gear and driving shaft through the driving chain to operate the engine oil pump and water pump. Its main feature is that the bracing rack is coupled on the driving shaft and interposed between the engine oil pump and a coupling holder. Hence the cantilever arm of the driving shaft can be supported firmer to enhance stability and durability of the engine oil pump. As shown in FIG. 1 of the aforesaid technique, the engine oil pump has an inner rotor and an outer rotor engaged locally, and the inner rotor and outer rotor form a gap between them to drive flowing of lubricant.

However, the conventional techniques set above rely on rotation of the engine to drive the engine oil pump's operation. The supply amount of the lubricant is proportional to the rotational speed of the engine. As a result, supply amount of the lubricant at high or low rotational speed does not meet actual requirements.

SUMMARY OF THE INVENTION

As the conventional engine oil pump supplies oil proportional to rotational speed of the engine, engine operation efficiency is lowered. The primary object of the present invention is to provide an engine oil pump that can adjust suitable oil supply amount corresponding to engine rotational speed.

The present invention provides an engine oil pump that provides automatic adjustment of oil supply amount. It includes an oil supply mechanism and an adjustment mechanism. The oil supply mechanism includes an oil inlet, an oil outlet, an oil passage with two ends communicating with the oil inlet and oil outlet, and a driving gear and a driven gear located in the oil passage that are engaged with each other. The driving gear and driven gear are engaged at a selected depth to determine oil supply amount passing through the oil passage. The adjustment mechanism includes a housing and an actuation piston fastened to the driven gear. The housing has a housing space to hold the actuation piston and an engine oil duct on the periphery thereof communicating with the housing space. The engine oil duct has one end communicating with the oil outlet. The engine oil duct receives engine oil from the oil outlet and stores the engine oil at one side of the actuation piston. The actuation piston is pushed by the pressure of the engine oil to drive the driven gear to move. By changing the relative positions of the driven gear and driving gear, oil supply amount can also be changed.

Thus at high rotational speed of the engine, the pressure of the engine oil at the oil outlet is higher. The pressure exerted to the actuation piston through the engine oil duct also increases to push the actuation piston to move. Since the actuation piston is coupled with the driven gear, the driven gear also is moved. As a result, while the engaged area of the driven gear and driving gear changes, the oil supply amount of the oil supply mechanism also changes.

By means of the foregoing technique, oversupply of the engine oil can be prevented at high engine rotational speed, and engine operation efficiency can be maintained as desired.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the engine oil pump of the invention.

FIG. 2 is another exploded view of the engine oil pump of the invention.

FIG. 3 is a sectional view of the engine oil pump of the invention at a low engine rotational speed.

FIG. 4 is another sectional view of the engine oil pump of the invention at a low engine rotational speed.

FIG. 5 is a sectional view of the engine oil pump of the invention at a high engine rotational speed.

FIG. 6 is another sectional view of the engine oil pump of the invention at a high engine rotational speed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2, the engine oil pump according to the invention includes an oil supply mechanism 1 and an adjustment mechanism 2. The oil supply mechanism 1 includes an oil inlet 11, an oil outlet 12, an oil passage 13 with two ends communicating with the oil inlet 11 and oil outlet 12, and a driving gear 14 and a driven gear 15 located in the oil passage 13 that are engaged with each other. The oil inlet 11 is connected to an engine oil storage device (not shown in the drawings) which is known in the art, thus details are omitted herein. The oil outlet 12 is connected to an engine (not shown in the drawings). When the engine oil is introduced from the oil inlet 11, it passes through the oil passage 13 and enters the engine through the oil outlet 12. The driving gear 14 and driven gear 15 are located in the oil passage 13. The driving gear 14 is driven by the engine. The driven gear 15 also is rotated due to being engaged with the driving gear 14. The driving gear 14 and driven gear 15 are engaged and rotated together to squeeze the engaged area to generate pressure in the oil passage 13. In the event that the engaged area of the driving gear 14 and driven gear 15 decreases, the pressure at the oil outlet 12 also reduces naturally. Hence the engaged depth of the driving gear 14 and driven gear 15 determines oil supply amount passing through the oil passage 13. The adjustment mechanism 2 includes a housing 21 which has a housing space 212 inside and an engine oil duct 211 on the periphery thereof communicating with the housing space 212. The engine oil duct 212 has one end communicating with the oil outlet 12. The engine oil duct 211 is preferably connected to one end of the oil passage 13 close to the oil outlet 12. The housing space 212 holds an actuation piston 23 fastened to the driven gear 15. The engine oil duct 211 introduces the engine oil from the oil outlet 12 to one side of the actuation piston 23 for storing. The actuation piston 23 is pushed by the pressure of the engine oil to drive the driven gear 15 to move. By changing the relative positions of the driven gear 15 and driving gear 14, oil supply amount can also be changed. Hence at high engine rotational speed, the pressure of the engine oil pushes the actuation piston 23 held in the housing 21 to drive the driven gear 15. When the driven gear 15 and driving gear 14 are engaged at a smaller depth (with overlapped portion decreased), the oil amount carried by the driving gear 14 and driven gear 15 to pass through the oil passage 13 also is decreased. Please refer to FIGS. 1 and 2 for an embodiment for the structure previously discussed. The housing space 212 further includes an actuator casing 22 held in the housing space 212 of the housing 21. The actuator casing 22 has a moving space 221 to constrain movement of the actuation piston 23. The actuator casing 22 further has at least one directing vent 222 on the periphery to direct the engine oil flowed into the housing 21 to one side of the actuation piston 23. Preferably, the actuator casing 22 has a plurality of directing vents 222 formed thereon communicating with the moving space 221. Moreover, the housing 21 has an inner wall of the housing space 212 with at least one directing groove 214 formed thereon to direct the engine oil from the engine oil duct 211 to the directing vents 222. In addition, the housing 21 and actuator casing 22 have respectively an opening 213 and 223 run through by the actuation piston 23 to couple with an axle 16 of the driven gear 15. The actuation piston 23 has at least one sealing ring 26 coupled thereon to prevent the engine oil from permeating into the moving space 221 through the openings 213 and 223. The engine oil is exerted to the actuation piston 23 held in the moving space 221 through the engine oil duct 211 of the housing 21 and directing vent 222 of the actuator casing 22. Furthermore, the moving space 221 holds an elastic element 24 in the actuator casing 22. The actuator casing 22 also is coupled with a cap 25. The cap 25 seals the elastic element 24 and actuation piston 23 in the actuator casing 22. The elastic element 24 butts another side of the actuation piston 23 to provide return elastic force when the actuation piston 23 is pushed by pressure of the engine oil. Hence, when the engine rotational speed increases (referring to FIGS. 5 and 6), the pressure of the engine oil at the oil outlet 12 increases to push the actuation piston 23 to move, and the driven gear 15 also is driven and moved at the same time. As a result, the engaged depth of the driven gear 15 and driving gear 14 decreases (overlapped portion decreased), the oil amount carried by the driving gear 14 and driven gear 15 to pass through the oil passage 13 also decreases. At a lower engine rotational speed (referring to FIGS. 3 and 4), the pressure exerted on the actuation piston 23 decreases, the elastic element 24 provides the elastic force to push the actuation piston 23 to be returned back, and the driving gear 14 and the driven gear 15 are engaged at a greater depth. Therefore, oil supply amount at the lower engine rotational speed increases.

While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.

In summation of the above description, the present invention provides a significant improvement over the conventional techniques and complies with the patent application requirements, and is submitted for review and granting of the commensurate patent rights. 

What is claimed is:
 1. An engine oil pump provided automatic adjustment of oil supply amount, comprising an oil supply mechanism and an adjustment mechanism, wherein: the oil supply mechanism includes an oil inlet, an oil outlet, an oil passage with two ends communicating with the oil inlet and the oil outlet, and a driving gear and a driven gear located in the oil passage that being engaged with each other; the driving gear and the driven gear being engaged at a selected depth to determine oil supply amount passing through the oil passage; and the adjustment mechanism includes: a housing which includes a housing space and an engine oil duct located on the periphery of the housing communicating with the housing space and including one end communicating with the oil outlet; and an actuation piston held in the housing space and fastened to the driven gear, the engine oil duct introducing engine oil from the oil outlet to one side of the actuation piston for storing, the actuation piston being pushed by pressure of the engine oil to drive the driven gear to move so that relative positions of the driven gear and the driving gear are changed to alter the oil supply amount.
 2. The engine oil pump of claim 1, wherein the housing space includes an actuator casing held in the housing space of the housing, the actuator casing including a moving space to constrain movement of the actuation piston and at least one directing vent on the periphery thereof to direct the engine oil flowed into the housing to the side of the actuation piston.
 3. The engine oil pump of claim 2, wherein the moving space includes an elastic element butting another side of the actuation piston.
 4. The engine oil pump of claim 2, wherein the housing and the actuator casing include respectively an opening to allow the actuation piston to couple with the driven gear.
 5. The engine oil pump of claim 2, wherein the actuator casing includes a plurality of directing vents on the periphery and the housing includes at least one directing groove to direct the engine oil from the engine oil duct to the directing vents.
 6. The engine oil pump of claim 3, wherein the actuator casing further is coupled with a cap to seal the elastic element and the actuation piston in the actuator casing.
 7. The engine oil pump of claim 1, wherein the engine oil duct is connected to one end of the oil passage close to the oil outlet.
 8. The engine oil pump of claim 1, wherein the oil outlet is connected to an engine to supply the engine oil to the engine, the driving gear being driven with the engine. 